function handleInput(input: unknown){
    // Type Guard
    if(typeof input === "string"){
        console.log(input.toLowerCase());
    }else if(typeof input === 'number'){
        console.log(input.toFixed(2));
    }else{
        console.log("Unknown type");
    }
}

handleInput('hello')    // hello
handleInput(3)          // 3.00
handleInput(true)       // Unknown type
